If we are including regents, then, we must include the Satavahana queen Naganika, wife of Satakarni (180-170 BCE? or early CE?), who acted as regent and carried on the administration after the death of her husband, because their son Vedasri was a minor (based on Naneghat inscription).

Suresh. 

On Wed, Nov 2, 2016 at 7:22 AM, Dominic Goodall <dominic.goodall@gmail.com> wrote:
Do widowed queens who continued as regents after their husbands’ deaths not count?

Surely there must be a few of these from much earlier periods. Prabhāvatī Guptā is one.  Another from further afield might be Kulaprabhāvatī, known from a fifth-century Cambodian inscription that seems to have been composed after her husband’s death (K. 875, Journal of the Greater India Society IV, p.117).

Dominic Goodall